Speaker 1: Welcome to Stuff to Blow Your Mind production of iHeartRadio.
Speaker 2: Hey you welcome to Stuff to Blow Your Mind. My
Speaker 2: name is Robert Lamb.
Speaker 3: And I am Joe McCormick, and we're back with part
Speaker 3: two in our series on the theme of licking with
Speaker 3: the tongue. In part one of this series, we talked
Speaker 3: about the role of licking in ancient Egyptian magic, which
Speaker 3: spans everything from the blessed licks and laps of the
Speaker 3: cow goddess Hathor to the sorceress violence of the crocodile
Speaker 3: who licks off the protective spells of the dead, and
Speaker 3: that discussion led to some diversions to talk about things
Speaker 3: like the adaptive function of the snake's forked tongue licking
Speaker 3: the air and the role that plays in chemo sensation
Speaker 3: and research about when children acquire a disgust reaction to
Speaker 3: contamination of food surfaces by licking. After that, we took
Speaker 3: a hard pivot into candyland and talked about the frankly
Speaker 3: shocking amount of research that has gone into the question
Speaker 3: how many licks does it take to get to the
Speaker 3: center of a tutsi pop, which is a deep rabbit
Speaker 3: hole that becomes more philosophically interesting that the longer you
Speaker 3: gaze into it.
Speaker 2: Yeah, I keep thinking about those TUTSI roll experiments. I
Speaker 2: think pretty much most, if not all of them were
Speaker 2: I think, at least on some level and in some
Speaker 2: phase approached with a fair amount of wit and whimsy.
Speaker 2: But you get the sense that like, once these scientific
Speaker 2: minds started digging into it, like it just becomes irresistible.
Speaker 2: It's just you've got to follow it through and put
Speaker 2: in the work.
Speaker 3: So we're back today to talk about licking some more.
Speaker 3: And I promised that in today's episode we would talk
Speaker 3: about wound licking behavior in animals, So I think that's
Speaker 3: where we want to start. First of all, just Rob,
Speaker 3: I've got a few photos for you to look at
Speaker 3: in the outline here that are various statues of a
Speaker 3: Catholic saint. No as I'm a little confused about how
Speaker 3: to pronounce this guy's name because it's spelled different ways
Speaker 3: in different languages. I believe it's Saint Roche or Saint Rock,
Speaker 3: sometimes spelled r o c h, sometimes spelled r c
Speaker 3: K or rck e or rch e anyway, a Catholic
Speaker 3: saint widely associated with hospitals, and with the Black Death.
Speaker 3: I was looking at a gallery page about him and
Speaker 3: some artworks of him from the Met Museum, which are
Speaker 3: talking pointing out that very often depictions of this saint,
Speaker 3: he is shown with his left hand touching a sore
Speaker 3: on his thigh, which that explains why so many of
Speaker 3: the images of this saint he looks like literally like
Speaker 3: he's trying to show a little leg, like he's lifting
Speaker 3: something up. He's like, hey, have a look at my
Speaker 3: thigh here.
Speaker 2: Yeah, in many cases too, or in some depictions it's
Speaker 2: like he's wearing shorts, so with like both legs on
Speaker 2: full display.
Speaker 3: Yeah, into these leggy outfits. Often also he has a
Speaker 3: dog beside him, and both the showing of the sore
Speaker 3: on his leg, there's like a sore on his thigh
Speaker 3: showing this bulge or sore on his thigh and the
Speaker 3: dog beside him connect to this legend about the Saint
Speaker 3: that he at one point was traveling. I think he
Speaker 3: was on a pilgrimage and he became very ill. I
Speaker 3: don't know if he got the plague or some other illness.
Speaker 3: The boil or the bulge would sort of connect to
Speaker 3: the idea that he got bubonic plague. But he fell
Speaker 3: ill and he collapsed somewhere, But then he was miraculously
Speaker 3: healed by a dog, a dog that brought him bread
Speaker 3: and licked his wounds.
Speaker 2: And in fact, in these various depictions you'll see the
Speaker 2: dog either carrying the bread, holding the bread up to
Speaker 2: the man, or sometimes looks like maybe the bread is
Speaker 2: on the ground next to the dog. I guess the
Speaker 2: dog brought it and dropped it like here you go.
Speaker 3: And in fact, this is not even the only major
Speaker 3: figure in Christianity to be part of a dog licking
Speaker 3: sores or dog licking his wounds motif that is said
Speaker 3: about the poor man Lazarus in the story in the Bible.
Speaker 3: Do you remember the rob Oh? Yes, the parable Jesus
Speaker 3: tells like he's ill and he falls down and the
Speaker 3: dogs lick his sores. It always seemed kind of gross.
Speaker 3: And by the way, I just I'll explain more about
Speaker 3: this as we go on in a few minutes here,
Speaker 3: but I want to say at the top, having a
Speaker 3: dog lick your wounds is not a reliable way to
Speaker 3: be healed of illness or to treat injuries.
Speaker 2: Yes, no matter what you might hear on Instagram or
Speaker 2: TikTok about the latest wound healing trend that's sweeping the nation.
Speaker 3: It's all natural, it really is, but there are reasons
Speaker 3: even though it's not actually advisable, there are reasons why
Speaker 3: people get there mentally to think, oh, a dog healed
Speaker 3: me by licking my wounds. So in the last episode
Speaker 3: we talked about the licking of injuries in the Egyptian
Speaker 3: magical context and how that was probably modeled on the
Speaker 3: observation of animals licking their wounds in nature. So I
Speaker 3: was wondering, first of all, which animals do and do
Speaker 3: not lick their wounds. Unfortunately, I don't think I can
Speaker 3: issue any kind of categorical taxonomic statement on this. It's
Speaker 3: not like, oh, mammals do it, and no other animals do.
Speaker 3: The best I can do is offer a kind of
Speaker 3: generalization and incomplete list of animals that have been observed
Speaker 3: licking cuts and punctures in the skin. The behavior does
Speaker 3: seem to be most prevalent in mammals, though not present
Speaker 3: in all mammals and probably not completely limited to them,
Speaker 3: But animals that lick wounds include rodents like mice and rats,
Speaker 3: and a lot of the research on the biology of
Speaker 3: wound licking has been performed in mice and rats. For example,
Speaker 3: there's research showing that in domesticated brown rats, wounds heal
Speaker 3: fast or when the rat is able to reach the
Speaker 3: wound with its mouth to lick it. And this in
Speaker 3: itself kind of highlights some features of wound looking adaptations,
Speaker 3: One that they do seem to help things heal, but
Speaker 3: also that in a lot of animals, self directed licking
Speaker 3: is going to be limited by what parts of the
Speaker 3: body the animal can reach with its own mouth. Some
Speaker 3: animals are more flexible than others.
Speaker 2: Right, right, right, So certainly we think about our own case,
Speaker 2: like we cannot lick every part of our own body
Speaker 2: that we might desire to lick because.
Speaker 3: Of our wound cut on the elbow. You're out of luck. Yeah. Also,
Speaker 3: animals that lick their wounds include many primates humans. Also,
Speaker 3: to some extent, there does appear to be at least
Speaker 3: some latent wound looking instinct in humans, though obviously lots
Speaker 3: of humans don't do it, and there are good reasons
Speaker 3: not to do it if you have other options, which
Speaker 3: most people do, but most I don't know about. Most
Speaker 3: many primates seem to have a wound looking instinct. Monkeys
Speaker 3: and apes or observed to lick wounds in nature. Some carnivores,
Speaker 3: including domestic dogs and cats, lick their wounds. Of course,
Speaker 3: some wild ungulates, such as deer bears lick their wounds.
Speaker 3: Maybe not all bears, but some bears at least. There
Speaker 3: are some reports that horses occasionally lick wounds, but I
Speaker 3: don't know. I was trying to sort this out. Evidence
Speaker 3: on that seems mixed to me. But it's also not
Speaker 3: just mammals, especially if you expand the definition of licking
Speaker 3: a little bit, like I see some reports online of
Speaker 3: anecdotal reports of people who keep reptiles like certain lizards,
Speaker 3: talking about the lizard's licking wounds. But again, the evidence
Speaker 3: is a little fuzzy. In this case, however, there is
Speaker 3: a scientifically recognized behavior in some ant species where injured
Speaker 3: worker ants will be brought back to the colony for
Speaker 3: medical treatment, which essentially amounts to having their wounds licked
Speaker 3: by first aid ants. It's not exactly licking with a
Speaker 3: mammalian tongue, but the wound treating ants will get the
Speaker 3: injured ant, and maybe it's been injured on a raid
Speaker 3: against a bunch of termites, and they'll get the injured
Speaker 3: ant and bring it back and treat the wound site
Speaker 3: by touching it with their mouth parts and applying saliva,
Speaker 3: which helps prevent infection and promotes healing. According to a
Speaker 3: twenty eighteen article by Frank Verhon and Linsen Mayer in
Speaker 3: the species Megaponera analysis, they found that quote lack of treatment.
Speaker 3: Lack of treatment by this licking procedure increased mortality from
Speaker 3: ten percent to eighty percent within twenty four hours, most
Speaker 3: likely due to infections. So being able to get this
Speaker 3: licking treatment from the other ants makes a huge difference
Speaker 3: in survival rates. So if a bunch of animals do
Speaker 3: lick wounds, that raises the question why what are the
Speaker 3: potential benefits of wound licking. It turns out there are
Speaker 3: a bunch first, and I think this one is underappreciated
Speaker 3: in some sources that really focus exclusively on the healing
Speaker 3: properties of saliva. The first thing to mention is the
Speaker 3: mechanical cleaning of the wound area by the tongue. Licking
Speaker 3: the wound can remove necrotic or dead tissue, especially if
Speaker 3: it's only very loosely attached at this point can remove
Speaker 3: dead or dyeing tissue from the wound area. This is
Speaker 3: called dibridement in a surgical context. And licking also, more
Speaker 3: importantly probably removes dirt and other material contaminants from the
Speaker 3: environment from the site of the injury. This is really
Speaker 3: important because dirt and other contaminating solids and some liquids
Speaker 3: are potentially microbial delivery vehicles. They have bacteria and other
Speaker 3: microbes on them and in them. And if say a
Speaker 3: little fleck of soil remains in an open wound, the
Speaker 3: microbes that are densely packed in that soil can move
Speaker 3: from the fleck of soil to the exposed tissue and
Speaker 3: cause an infection. And so licking with the tongue mechanically
Speaker 3: scrapes that fleck of soil out of the wound so
Speaker 3: that it doesn't become a landing craft for a microbial army.
Speaker 3: And note that this is the same reason that doctors
Speaker 3: would advise you to wash a wound as soon as
Speaker 3: possible after you get hurt. Washing a wound out with water, soap,
Speaker 3: and water performs the same function as licking. Here it
Speaker 3: physically removes contaminants that bring a payload of germs with them.
Speaker 2: So basically, whatever is in a dog saliva, there may
Speaker 2: already be things far worse than dog saliva in the wound. Yes,
Speaker 2: so the tongue can just physically remove those again, almost
Speaker 2: like you were rinsing out a wound, which of course
Speaker 2: the dog can't do because it doesn't have access to
Speaker 2: modern medical science and so forth.
Speaker 3: Exactly, Yes, so the dog's tongue, for the dog, is
Speaker 3: the best it can do because it doesn't have clean
Speaker 3: running tapwater. Second, when animals lick a wound, they not
Speaker 3: only get rid of the bad stuff, but they also
Speaker 3: introduce substances to the wound through their saliva that may
Speaker 3: help the wound heal. Some examples here antimicrobial enzymes in
Speaker 3: our saliva that selectively kill germs on contact. A common
Speaker 3: example here is the enzyme lysizyme. This is found in
Speaker 3: a bunch of our body fluids. Actually it's in spit,
Speaker 3: but also tears nasal and epithelial mucus in milk, and
Speaker 3: also in non human body fluids like egg whites. Lysisyme
Speaker 3: selectively attacks GRAM positive bacteria by dissolving their cell walls.
Speaker 3: So if bacteria made horror movies, lysizyme might be a
Speaker 3: good candidate for a melt movie monster. You know, it
Speaker 3: just kind of it melts you. It dissolves your you know,
Speaker 3: the outside of the cells. Another anti my chrobial in
Speaker 3: saliva is called lactoferrin. This is a protein that prevents
Speaker 3: bacteria from growing by starving them of iron. Bacteria need
Speaker 3: iron atoms to reproduce, and lactoferriin bonds to free iron,
Speaker 3: making it unavailable for the bacterial cells. This is called
Speaker 3: iron sequestration. Removes the iron from them and so that
Speaker 3: they can't get what they need in order to grow
Speaker 3: and survive. And that's not even a whole list. Animals
Speaker 3: just have a big host of antibacterial agents in their saliva.
Speaker 3: And note that these antibacterial agents in the saliva wouldn't
Speaker 3: be evolved exclusively for the application to external wounds. They
Speaker 3: play a big role in protecting the body in the mouth,
Speaker 3: like they're doing stuff for your body in your mouth,
Speaker 3: for your digestive system, and for your mouth cavity. Spit
Speaker 3: also contains things that are not just antimicrobials, but things
Speaker 3: that can actively speed up the healing process in the
Speaker 3: affected tissue. And this includes his statins. These are proteins
Speaker 3: that also have antimicrobial properties, but in addition to that,
Speaker 3: they promote healing by causing what's called epithelial migration. They
Speaker 3: cause epithelial cells to migrate to the exposed tissue surface
Speaker 3: and close the wound. And saliva also has growth factor
Speaker 3: proteins like epithelial growth factor and nerve growth factor, and
Speaker 3: you can see some of these influences at work. Actually,
Speaker 3: if you have ever noticed that injuries inside your mouth
Speaker 3: tend to heal a good bit faster than injuries on
Speaker 3: your outer skin.
Speaker 2: Hmmm, I mean that that can be a kind of
Speaker 2: a paradox to consider because sometimes wounds inside your mouth
Speaker 2: are a little more irritating then wounds on your outer skin,
Speaker 2: so they might feel like they hang around longer. So
Speaker 2: I don't know, I'll have to really calculate on this one.
Speaker 3: Well, they might actually hang around longer, depending on things
Speaker 3: like if you keep if something keeps irritating them or
Speaker 3: keeps reopening the.
Speaker 2: Wound a sharp the wheat, then yes, yeah, if.
Speaker 3: You keep cutting it open over and over, like, because
Speaker 3: you're using your mouth in a way that like you know,
Speaker 3: you could actually just keep stuff away from a cut
Speaker 3: on your skin, so there could be ways that something
Speaker 3: in your mouth would last longer, but it is typically
Speaker 3: the case that abrasions and cuts on the oral mucosa
Speaker 3: heal faster than on the outside of the body. And
Speaker 3: one reason for this not the only reason, probably, but
Speaker 3: one reason is the presence of these healing factors and
Speaker 3: antimicrobial agents within the saliva, so a lot of benefits
Speaker 3: in spit. Spit could do a lot for an open wound,
Speaker 3: but these benefits do not come free. Wound looking, in fact,
Speaker 3: has a very high cost. It comes with risks. At
Speaker 3: the same time that it removes contaminants, provides antimicrobial enzymes,
Speaker 3: and stimulates healing, it also so introduces problems of its own.
Speaker 3: For example, failure to regulate the wound looking behavior can
Speaker 3: lead to overlocking, which itself almost creates new wounds or
Speaker 3: makes the wound worse kind of keeps it from healing.
Speaker 3: It can irritate or further injure the skin. A common
Speaker 3: example is that you know a dog just it has
Speaker 3: a wound looking instinct, but it can't turn the instinct off,
Speaker 3: so it just keeps licking a wound, making it actually
Speaker 3: worse and worse, So the injured dog will need a
Speaker 3: cone because it doesn't know when to stop.
Speaker 2: Okay, so that sometimes the cone is for that, I know.
Speaker 2: Sometimes a cone with an animal is also to keep
Speaker 2: them from licking off a medication, which of course they
Speaker 2: have not evolved to understand. Like for the natural world dog,
Speaker 2: the best medicine is the dog saliva. The idea that
Speaker 2: there is a better medicine out there that did not
Speaker 2: come from their mouth is an impossible idea.
Speaker 3: Right, So there can be multiple reasons for I mean,
Speaker 3: it can ye keep a dog from removing medication, can
Speaker 3: keep a dog from tearing out stitches, and can also
Speaker 3: just keep a dog from over grooming or overlicking a
Speaker 3: wound site. But maybe even more importantly, wound licking while
Speaker 3: it removes some contaminants and microbes, it introduces others. The
Speaker 3: mouth is not sterile, so it's going to be delivering
Speaker 3: bacteria from the mouth cavity to the wound and this
Speaker 3: does come with genuine risks, especially if the animal's oral
Speaker 3: health is poor, or if it has mouth infections, or
Speaker 3: if the animal's immune system is compromised, or if the
Speaker 3: animal just has an oral microbiome that is more dangerous
Speaker 3: to cross link to open wounds. So you might imagine
Speaker 3: that this could be the case with carnivores. A carnivore
Speaker 3: licking its wounds, that might be a riskier behavior than
Speaker 3: a herbivore licking its wounds on average, but still a
Speaker 3: lot of carnivores do it, so the benefits still seem
Speaker 3: to outweigh the costs in nature. So if it comes
Speaker 3: with these dangers, you can, you know, maybe contaminate the
Speaker 3: wound with bacteria from the mouth. If it comes with
Speaker 3: these dangers, why does the behavior continue? Why does it
Speaker 3: persist in nature? It just seems like it's a case
Speaker 3: of trade offs, and on average, the wound looking instinct
Speaker 3: does more good than harm in the animals where it persists,
Speaker 3: it helps and it causes harm, and it does a
Speaker 3: little bit more of the former than the latter. So
Speaker 3: it's the evolutionary math works out.
Speaker 2: Yeah, does it allow the individual animal in question to
Speaker 2: live long enough to do more reproduction? Essentially, like it
Speaker 2: kind of boils down to.
Speaker 3: That, Yeah, Or if it just you've got a wound
Speaker 3: and it makes things worse forty percent of the time,
Speaker 3: but makes things better seventy percent of the time, I'll
Speaker 3: take that you know, you know odd, or I guess
Speaker 3: the math I just proposed didn't work out, but seventy
Speaker 3: thirty I guess yeah, I just I don't know what
Speaker 3: the real numbers are. But anyway, with the knowledge of
Speaker 3: germ theory and modern medicine, we don't have to go
Speaker 3: with this math. Fortunately, because by washing out a wound
Speaker 3: with clean water and soap and applying clean pharmaceutical antimicrobials
Speaker 3: to the wound site, you can basically get all of
Speaker 3: the benefits of wound looking with none of the risks. Now,
Speaker 3: another interesting thing about wound locking is that there are
Speaker 3: two different versions of this behavior. There's the main kind
Speaker 3: we've been talking about, which is self directed wound loocking
Speaker 3: licking your own cut or scrape. But there's also what's
Speaker 3: called communal wound looking, licking the wounds of others of
Speaker 3: your species. I found a good quick review of the
Speaker 3: research on communal wound looking in the background section of
Speaker 3: a paper called Licking their Wounds Social Response to Trauma
Speaker 3: by free ranging Bison. This is by Thomas Young, Kayleye. Thacker,
Speaker 3: and Christopher Lewis, published in the journal Ethology in twenty
Speaker 3: twenty three, and they talk about how communal wound looking
Speaker 3: has broadly the same hygienic and healing acceleration benefits as
Speaker 3: self directed licking, but with some interesting added factors. One
Speaker 3: is that if animals in a group lick the wounds
Speaker 3: of other animals, this allows the treatment of wound sites
Speaker 3: that the animals cannot reach with their own mouths. So
Speaker 3: this gets around the flexibility problem.
Speaker 2: Right, especially if you're dealing I mean, you could be
Speaker 2: dealing with human beings again, but especially if you're thinking
Speaker 2: about large herbivores.
Speaker 3: Yeah, yeah, But also this is interesting there could be
Speaker 3: secondary social benefits which are parallel to the benefits of
Speaker 3: social grooming. Young and co authors note that group wound
Speaker 3: looking might trigger a release of the hormone oxytocin and
Speaker 3: other associated neurotransmitters, which could help reduce the stress of
Speaker 3: animals after a traumatic incident and could help strengthen social
Speaker 3: bonds among group members. So oxytocin chemically counteracts the effects
Speaker 3: of the hormone cortisol or stress hormone, and is thus
Speaker 3: used internally to deactivate the body's stress response. This can
Speaker 3: be really useful because while the stress response stress hormones
Speaker 3: are good for you in an emergency, like if you
Speaker 3: are about to run or fight for your life, they
Speaker 3: quickly become a harmful burden on the body if you
Speaker 3: are not about to run or fight for your life,
Speaker 3: so you want to turn them off whenever you don't
Speaker 3: need them. I think we could all use that and
Speaker 3: find a way to turn the stress hormones off more often.
Speaker 3: Oxytocin is also importantly involved in forming social bonds between individuals.
Speaker 3: It plays some kind of role in complex cognitive and
Speaker 3: social effects like love, devotion, and loyalty. Though it's important
Speaker 3: to flag some caveats here because the role of oxytocin
Speaker 3: socially and cognitively I think sometimes it gets oversimplified. Oxytocin
Speaker 3: is not the only hormone that is involved in this stuff,
Speaker 3: and it's also not like an automatic love potion that
Speaker 3: just mechanistically makes us love people when it is released.
Speaker 3: Love and loyalty and related emotions are complex and multi causal,
Speaker 3: and even the chemical influences that feed into them are many.
Speaker 3: But oxytocin is important, and so it's if it is
Speaker 3: released by this communal wound looking behavior the same way
Speaker 3: that it is sometimes released during grooming behaviors that could
Speaker 3: signal that that communal wound looking plays some role in
Speaker 3: strengthening or regulating maintaining social bonds within a group. Communal
Speaker 3: wound looking has also been observed in rodents, in primates,
Speaker 3: and in this study by Young and co authors, it
Speaker 3: was observed in social ungulates, specifically bison in northwestern Canada,
Speaker 3: which had been shot with tranquilizer darts so that they
Speaker 3: could be tagged for tracking the author's right quote. The
Speaker 3: day after being darted, we observe three different adult bison
Speaker 3: lick the wounds of the two wounded bison. Both bison
Speaker 3: were less than three meters, were within less than three
Speaker 3: meters of each other during this time, and all of
Speaker 3: the observed wound looking occurred in less than ten minutes.
Speaker 3: Our observation provides an additional example of communal wound locking
Speaker 3: in free ranging mammals and extends it to a social ungulate.
Speaker 3: Benefits to bison of communal wound looking are perhaps largely social,
Speaker 3: and that kind of brings me back to thoughts about
Speaker 3: these stories of dogs licking humans wounds. You know, this
Speaker 3: is an even further thing where it's like a cross
Speaker 3: species wound looking behavior kind of makes me think that
Speaker 3: that is cross species wound looking, I doubt is something
Speaker 3: that is directly specifically an evolved adaptation, but probably more
Speaker 3: like a you know, a misapplication of a general wound
Speaker 3: licking impulse that's primarily probably focused on a dog's own
Speaker 3: kind or its own ancestors.
Speaker 4: Yeah.
Speaker 2: Yeah, And I guess that one of the things that
Speaker 2: potentially complicates all of this, or a least adds another dimension,
Speaker 2: because so many things in animal behavior they're they're not
Speaker 2: so cleanly defined by one category. Is that of course,
Speaker 2: I mean just looking at the dog, right. A dog
Speaker 2: will also lick you in the face when there's not
Speaker 2: a wound there, That's right. One of my friend's dogs
Speaker 2: routinely just licks my pants the whole time I'm over
Speaker 2: at his house, and I'm not sure exactly why.
Speaker 3: Yeah, so there could be multiple different motivations going on
Speaker 3: for that kind of licking. Like it could be a
Speaker 3: social grooming kind of thing. It's a social behavior that is,
Speaker 3: you know, to help dogs relate to each other and
Speaker 3: maintain their relationships, something about bonding. It could be a
Speaker 3: it could just be a you know, like taste and
Speaker 3: texture thing like a dog is you know, it likes
Speaker 3: something it's getting from this licking feeling or from the
Speaker 3: licking taste there. It might I wonder if dogs licking
Speaker 3: human wounds could just be because they're getting some salty there.
Speaker 2: I mean, yeah, all of these things are kind of
Speaker 2: in play with some topics related to the cat we're
Speaker 2: about to get into, because I didn't really I didn't
Speaker 2: specifically look at cat wound licking though, as we already mentioned,
Speaker 2: like they are a type of organism that does this,
Speaker 2: but I was looking at various other forms of social licking,
Speaker 2: and yeah, it's one of these areas where there are
Speaker 2: a number of different overlaps and some competing and potential
Speaker 2: potentially overlapping theories as to why they engage in it,
Speaker 2: And a lot of it does come down to like
Speaker 2: social activity, the release of potential release of hormones, and
Speaker 2: how it makes the individual cat feel to groom or
Speaker 2: be groomed. So moving on to cats, then, if you
Speaker 2: have ever lived with a cat, I know that they
Speaker 2: have various tactile ways to make their feelings known. You
Speaker 2: may receive the scratch, you may get the wet and
Speaker 2: nose boop, the rub the head butt, the making of biscuits.
Speaker 2: Of course, the coveted lap set. You may also find
Speaker 2: yourself licked.
Speaker 3: A connoisseur of pet affection may notice a textural difference
Speaker 3: in cat licks and dog licks. I find that the
Speaker 3: dog's tongue is somewhat softer. The cat's tongue is somewhat rougher.
Speaker 2: Yes, due to the papilla on the cat Tonguehich I'll
Speaker 2: get into. It's like it's essentially their comb. As you've observed,
Speaker 2: cats will rigorously groom themselves with their tongue, and the
Speaker 2: papilla on their tongue allows them to essentially, you know,
Speaker 2: they work like the again, the teeth of a comb.
Speaker 2: And that's why it's a little bit scratchy. And that's
Speaker 2: why being licked by a cat is often a ticklish affair,
Speaker 2: one that caused for a certain amount of what's going on?
Speaker 2: Why is it happening? Sort of reaction.
Speaker 3: When I think about the cat's tongue, I pretty much
Speaker 3: always think of the eighteenth century English poet Christopher Smart,
Speaker 3: who wrote I think some of the best cat poetry
Speaker 3: of all time, in a section known as for I
Speaker 3: will consider my cat Jeffrey after the first line in
Speaker 3: the section in his devotional Christian poem Jubilate Agno, meaning
Speaker 3: rejoice in the lamb. Smart wrote this when he was
Speaker 3: confined to a mental institution in London called Saint Luke's
Speaker 3: Hospital for Lunatics. This was roughly in the middle of
Speaker 3: the eighteenth century. I know I've brought this poem up
Speaker 3: on the show before at some point.
Speaker 2: Yeah, because I remember one line in particular. Now that
Speaker 2: I'm looking at it again.
Speaker 3: I just love it. It's too long to read in
Speaker 3: full here, but I love it so much. I have
Speaker 3: to mention the part leading up to the part about
Speaker 3: the tongue, but then also one other highlight from later.
Speaker 3: So the section leading up to the tongue line goes
Speaker 3: like this, He's celebrating all of He's just adoring his cat,
Speaker 3: Jeffrey's celebrating all of Jeffrey's virtues. And Smart writes, for
Speaker 3: he is the quickest to his of any creature, for
Speaker 3: he is tenacious of his point. For he is a
Speaker 3: mixture of gravity and waggery. For he knows that God
Speaker 3: is his savior. For there is nothing sweeter than his
Speaker 3: peace when at rest. For there is nothing brisker than
Speaker 3: his life when in motion, for he is of the
Speaker 3: Lord's poor, and so indeed is he called by benevolence
Speaker 3: perpetually poor Jeffrey. Poor Jeffrey. The rat has bit thy throat.
Speaker 3: For I bless the name of the Lord Jesus, that
Speaker 3: Jeffrey is better, for the divine spirit comes about his
Speaker 3: body to sustain it in complete cat. For his tongue
Speaker 3: is exceeding pure, so that it has in purity what
Speaker 3: it wants in music.
Speaker 4: Beautiful.
Speaker 3: It really is beautiful. And that last line, So that's
Speaker 3: the line about the tongue. It's exceeding pure, it has
Speaker 3: in purity what it wants in music. I don't know
Speaker 3: if there's a meaning there that is going past me
Speaker 3: through cultural context or beliefs about cats at the time,
Speaker 3: but my interpretation is cat mau is just as good
Speaker 3: as human mouth, even though cat mouth cannot talk. Cat
Speaker 3: licks better than or equal to human words.
Speaker 2: Yeah, yeah, I would. I would agree with that. Like,
Speaker 2: I'm not a huge fan of my cat licking me,
Speaker 2: but when she does, I do acknowledge that it. I mean,
Speaker 2: I don't want to overstate it and be like it
Speaker 2: is an act of love or whatever, but at the
Speaker 2: very least. It is a neutral act, and I know
Speaker 2: that I am in okay graces with the animal at
Speaker 2: the moment. That's what we go to go for in
Speaker 2: this household, sustaining neutrality.
Speaker 3: I think it's okay to call that love. You understand,
Speaker 3: you know, you understand the differences in cats and humans.
Speaker 3: But still there's there's something there that you know, you
Speaker 3: can make that metaphorical.
Speaker 2: Leave yeah, as long as yeah, I know, I'm calling
Speaker 2: it love, So it's fine.
Speaker 3: The one other passage I wanted to read here, this
Speaker 3: is from sort of the end of the section about
Speaker 3: Jeffrey Smart rites. For by stroking of him, I have
Speaker 3: found out electricity. For I perceived God's light about him,
Speaker 3: both wax and fire. For the electrical fire is the
Speaker 3: spiritual substance which God sends from Heaven to sustain the bodies,
Speaker 3: both of man and beast. For God has blessed him
Speaker 3: in the variety of his movements. For though he cannot fly,
Speaker 3: he is an excellent clamberer. For his motions upon the
Speaker 3: face of the earth are more than any other quadruped.
Speaker 3: For he can tread to all the measures upon the music.
Speaker 3: For he can swim for life or he Can.
Speaker 2: Creep, Joe, you will be delighted to know that for
Speaker 2: He Can Creep is the title of an episode of
Speaker 2: the latest season of Love, Death, and Robots, and it
Speaker 2: is about a poet and a sanitarium and his beloved
Speaker 2: cat named Jeffrey stands against the forces of darkness and
Speaker 2: it's rather good.
Speaker 3: I haven't seen that show, but really tempted to watch
Speaker 3: now because yeah, I love for my cat Jeffrey.
Speaker 2: Yet features the voice of Jim Broadman as Christopher the Poet.
Speaker 3: Well, there's other stuff I couldn't get to here, so
Speaker 3: I just recommend anybody who wants to go look up
Speaker 3: the four I will consider my cat Jeffrey section of
Speaker 3: the poem Jubilate Agno. You can find it online.
Speaker 2: It's great, excellent, excellent. You know, I recently watched part
Speaker 2: of a series started it watching it with my kid,
Speaker 2: titled Night of the Living Cat. It is a Japanese
Speaker 2: animated series based on a manga and Takashi mi k
Speaker 2: played a hand in it. But it's so far at
Speaker 2: least it's totally age appropriate. But it's super fun because
Speaker 2: it's obviously a parody of zombie and apocalypse films, except
Speaker 2: The whole idea is that cats carry some sort of
Speaker 2: a virus, and if they come into contact with you,
Speaker 2: and certainly if they lick you, you too will become
Speaker 2: a cat. And so the population of the planet is
Speaker 2: swiftly becoming a population of cats.
Speaker 4: Whoa.
Speaker 3: So that's very much an inversion of the Christopher Smart
Speaker 3: idea about the purity of the tongue.
Speaker 2: Well, the show is pretty fun and that it also
Speaker 2: plays with the fact that even though humans recognize that
Speaker 2: the cats are bringing their destruction, they also still love cats,
Speaker 2: and so they can't bring themselves to do violence against
Speaker 2: cats or anything of that nature. It's just like a
Speaker 2: heartbreaking affair. It's pretty fun though so far, so I'd
Speaker 2: like that premise. Yeah, all right, Well, getting back into licking.
Speaker 2: Licking is of course just one way that cats communicate
Speaker 2: and or get information about the world. They may lick
Speaker 2: your skin out of curiosity, if you particularly. Theories vary
Speaker 2: on all this, but one idea is that they might
Speaker 2: lick you because your skin is salty, or you have
Speaker 2: something on your skin that is interesting. And I'm not
Speaker 2: sure there's a firm answer on any of that, but
Speaker 2: it just may be part of the scenario. So if
Speaker 2: your cat is licking you and there doesn't seem to
Speaker 2: be any rhyme or reason, it could just be that
Speaker 2: where they're just like, oh, salty interesting, or oh lotion interesting.
Speaker 2: Of course, as with any domesticated or semi domesticated animal,
Speaker 2: depending on how you view cats, the relationship that we
Speaker 2: have with house cats is complicated by all of this,
Speaker 2: of course, and in some ways whatever we have going
Speaker 2: on with the cat is a perversion of what would
Speaker 2: occur in nature. So in some ways, the best way
Speaker 2: to understand what they're licking of us means we have
Speaker 2: to look at how they interact with other cats in
Speaker 2: their natural environment, So especially looking at colonies of cats
Speaker 2: where a number of cats have essentially come together or
Speaker 2: kind of aggregated in such a way that they don't
Speaker 2: have to worry so much about food, they're not competing
Speaker 2: with each other, and they will find some sort of stability.
Speaker 2: Doesn't mean they all get along with each other, though,
Speaker 2: because cats will have and I've seen this term used
Speaker 2: multiple times, they will have preferred associates. To be clear,
Speaker 2: they do not have friends, they have preferred associates, which
Speaker 2: which I like. It sounds like cat legal eese.
Speaker 3: Maybe I've just got film noir on the brain because
Speaker 3: of the stuff we've been doing on Weird House Cinema.
Speaker 3: But I'm thinking of like Humphrey Bogart's associates in the
Speaker 3: noir films, people that he's not exactly lovely with, but
Speaker 3: you know, they they sort of have a working relationship.
Speaker 2: They tolerate, into some sense, depend on each other. Yeah,
Speaker 2: so among preferred associates you encounter a number of different actions.
Speaker 2: There's something called alla rubbing. This is when they rub
Speaker 2: their bodies and tails against each other as a form
Speaker 2: of social bonding and communication. So I think everyone has
Speaker 2: seen an example of this and with cats and other cats,
Speaker 2: but also anytime they rub against especially if they rub
Speaker 2: against your legs, this is seen as an extinct as
Speaker 2: an extension of this behavior. Now I'm not sure about
Speaker 2: feet because speaking mainly from my experience, rubbing against my
Speaker 2: feet often quickly devolves into play and play biting of
Speaker 2: my feet, and of course levels of play are going
Speaker 2: to occur, especially in younger cats, but even in older cats,
Speaker 2: and then indoor cats is kind of a forever kitten
Speaker 2: scenario by some estimates. So again, another example where you
Speaker 2: can't just talk about the social behavior among preferred associates,
Speaker 2: because it could descend into play at any point, and
Speaker 2: that's another factor in everything.
Speaker 4: I know.
Speaker 3: This is asking you to get inside the mind of
Speaker 3: a cat, which may be impossible. But you've talked before
Speaker 3: about your cat having a habit of attacking your feet
Speaker 3: out from underneath furniture. Do you get the sense that
Speaker 3: your cat in the moment is thinking of your feet
Speaker 3: as part of your body or are the feet just
Speaker 3: something that's moving? Does that make sense?
Speaker 2: That's a complicated question and one that I've I've heard
Speaker 2: more broadly explored a lot of times just talking about
Speaker 2: what do cats think humans are? And I've heard the
Speaker 2: argument that, you know, they think that we're other cats,
Speaker 2: and if they think that there were other cat, other cats,
Speaker 2: then it makes sense to engage in play with us.
Speaker 2: Play generally takes the form of fake fighting.
Speaker 4: I know.
Speaker 2: Another thing that my cat will do is come up
Speaker 2: next to my foot, my sockt foot, PLoP down next
Speaker 2: to that foot, way too close to my foot, as
Speaker 2: if inviting me to rub against her. And even if
Speaker 2: I don't rub against her, she may just start attacking
Speaker 2: my foot. So so like that's one way, But then
Speaker 2: there's there's also the idea that cats see us as
Speaker 2: part of their environment as well, so like we we
Speaker 2: also have sort of like a deep personified status to
Speaker 2: some degree where we are just part of the place
Speaker 2: that they are comfortable with. And I mean, we can
Speaker 2: certainly understand that when they use us as a heated
Speaker 2: bed and just want to sit on this all the
Speaker 2: time during the colder months.
Speaker 3: Are we warm moving furniture?
Speaker 2: Yeah, So I don't know. I'm willing to bet there's
Speaker 2: maybe a little bit of both of these scenarios going on.
Speaker 2: And you know, the cat is going to have a
Speaker 2: you know, probably from our standpoint, a perplexing understanding of
Speaker 2: other beings, Like they're not going to perceive other beings
Speaker 2: the same way we do. We're going to and it's
Speaker 2: probably a lot easier to understand their perception of definite
Speaker 2: prey or predator status organisms.
Speaker 3: Maybe it was not a meaningful question, No.
Speaker 2: No, I think it's a fascinating quest when I think
Speaker 2: about all the time I lock eyes with this creature
Speaker 2: across the room, and I'm like, what does she think
Speaker 2: I am?
Speaker 1: Like?
Speaker 2: What am I to her? And indeed, then I turn around.
Speaker 2: What is she to me? I don't know. These are
Speaker 2: difficult questions to ask. But coming back to alo rubbing,
Speaker 2: there is this seeming we might think of it as
Speaker 2: an emotional context to it as well. I was reading
Speaker 2: two thousand five Understanding Feline Signaling and Social Interactions. This
Speaker 2: is from the proceedings of the North American Veterinary Conference
Speaker 2: by Sharon L. Crowell Davis, and she pointed out that
Speaker 2: in many ways this just is this rubbing of cats
Speaker 2: against each other, and indeed a rubbing of a cat
Speaker 2: against your leg. It's in many ways like a hug,
Speaker 2: like it's comforting to them in the same way that
Speaker 2: like other activities they do seem to be based purely
Speaker 2: on comfort. Like for instance, cats will often be in
Speaker 2: physical contact with each other while they are sleeping and
Speaker 2: during the during cold months or cold environments, and again
Speaker 2: cold by a cat standards, which is a little different
Speaker 2: than human standards. It makes sense, right while they're sharing
Speaker 2: each other's body heat. But they'll also do it even
Speaker 2: if thermoregulation doesn't seem to be an issue. If it's
Speaker 2: you know, hotter, warmer, and so forth, it may be
Speaker 2: that they do these things, you know, just because it
Speaker 2: is comforting to do them, and that gets to straight
Speaker 2: up grooming as well. In the of licking a fur,
Speaker 2: this is something that may be acquired and when they're
Speaker 2: kittens it's comforting behavior. It might also be a way
Speaker 2: to mark others. As we'll discuss a little bit more.
Speaker 2: And as Carole Davis points out, humans have this terrible
Speaker 2: sense of smell. We just can't we can't smell at all,
Speaker 2: We've discussed as many times before, at anywhere close to
Speaker 2: the same level as even a cat, and certainly not
Speaker 2: a dog. So just it becomes very difficult for us
Speaker 2: to understand or comprehend the olfactory lives of animals like this,
Speaker 2: Like not only not just like a chemical understand like
Speaker 2: we can sort of break down the chemical understanding of
Speaker 2: chemical markers, but in terms of like translating that into
Speaker 2: our like sort of larger understanding of how animals operate
Speaker 2: in the world, it can be challenging.
Speaker 3: Yeah, they have an information rich relationship to the environment
Speaker 3: on a dimension that where we come nowhere close.
Speaker 2: Right, But getting back to where we're talking about with dogs,
Speaker 2: with cats too, licking and grooming or soothing behaviors, it
Speaker 2: stirs the release of endorphins. They may lick themselves, other
Speaker 2: cats or humans, or also materials in the home, and
Speaker 2: this can certainly spill over into excessive licking that may
Speaker 2: be a sign of stress or some other situation, but
Speaker 2: in general, it's like this is a calming action that
Speaker 2: they can partake of.
Speaker 4: Now.
Speaker 2: On top of that, of course, cats are famous for
Speaker 2: their use of self licking to fastidiously clean their own bodies,
Speaker 2: a self grooming process that takes up a substantial portion
Speaker 2: of their waking hours. I've seen different estimates on that
Speaker 2: this mostly I've seen an estimate of between thirty and
Speaker 2: forty percent of their waking hours, and this can amount
Speaker 2: to something like five hours apparently of just endless grooming.
Speaker 2: Cat owners will have noticed this, especially if your cat
Speaker 2: does want to treat you like a couch and then
Speaker 2: is like, hey, I'm not just going to sit here
Speaker 2: and watch television with you, I'm also going to clean myself.
Speaker 2: And then you're like, I don't want this anymore, and
Speaker 2: you have to push them off or gently push them off,
Speaker 2: or maybe you can put up with it. I find
Speaker 2: it a little hard to put up with, but but yeah,
Speaker 2: I've also seen like eight percent estimates. But anyway you
Speaker 2: cut it, they spend a lot of time self grooming,
Speaker 2: looking after their fur, cleaning it. And as I mentioned earlier,
Speaker 2: part of it is, you know, using those little barbs
Speaker 2: in their tongue, the sandpaper of their tongue to physically
Speaker 2: clean their furs. There's a little backward facing barbs and
Speaker 2: helps remove like little particles from their fur, kind of
Speaker 2: getting back to the womb cleaning that we were talking
Speaker 2: about earlier.
Speaker 4: Yeah. Yeah.
Speaker 2: On top of just the mechanical cleaning of their fur,
Speaker 2: self grooming also enables them to spread natural oils across
Speaker 2: their coat, helps keep it clean, waterproof and insulated. Also,
Speaker 2: as the saliva evaporates, it can also help cool them
Speaker 2: down as a means of thermoregulation. So that's seems to
Speaker 2: be in play as well. And then of course the
Speaker 2: act itself is self soothing. They are in there. You
Speaker 2: could almost say happy place if they are self grooming. Now,
Speaker 2: when it comes back to the human question, I did
Speaker 2: find a nice little explainer article that tackles this and
Speaker 2: covers some of the ground we've already discussed. This was
Speaker 2: for BBC Science Focus from I think a couple of
Speaker 2: years ago by Thomas Ling, and he basically broke it
Speaker 2: down into three different theories. The trust theory that they're
Speaker 2: making a display of trust towards you. My cat is
Speaker 2: licking me because they are saying you, I trust you
Speaker 2: are good, You are a preferred associate. Then there's the
Speaker 2: biochemical theory that there's something about your taste that's interesting, okay,
Speaker 2: salt your lotion or what have you. And then there's
Speaker 2: the possession play theory, and this is that they are
Speaker 2: marking you as their own. They're saying like, this person
Speaker 2: is my territory, this person is my property. And so
Speaker 2: going through each of these, starting with the trust theory,
Speaker 2: this is I think relatable to the oligrooming scenario, which
Speaker 2: means at best or a preferred affiliate. This should not
Speaker 2: be confused with love. If we're talking, you know, purely
Speaker 2: scientifically about the scenario. Again, we humans can call it love,
Speaker 2: but maybe just understand that in the literature they're not
Speaker 2: going to call it that.
Speaker 4: But yeah.
Speaker 2: Studies have shown though that any supposed trust bond that
Speaker 2: a cat is associating with a human, it doesn't necessarily
Speaker 2: mean it's absolute. So cats tend to be pretty solitary
Speaker 2: in many cases, and in studies they found that they
Speaker 2: get along well with strangers almost just as well or
Speaker 2: as just as well as they would with other humans,
Speaker 2: which cat owners I think sometimes observe this because in
Speaker 2: our closed environments where we think about, oh, the cat,
Speaker 2: she's so social, she loves us so much, she just
Speaker 2: wants to be around us. And I'm not discounting any
Speaker 2: of the social needs of cats, but it can also
Speaker 2: be a little bit alarming when a stranger comes over
Speaker 2: and it's like, cat's right in their lap and you're like,
Speaker 2: you want to be like, you don't know that person
Speaker 2: at all. Why weren't you said, in my lap? So, yeah,
Speaker 2: that's one caveat to the trust theory. I think we've
Speaker 2: hit the biochemical theory pretty well, and then the possession
Speaker 2: play theory basically comes down to the idea that the
Speaker 2: cat's own smell is the most important thing to it
Speaker 2: in terms of its olfactory world, Like, it wants to
Speaker 2: make sure it smells like itself, so it will lick
Speaker 2: away any foreign smells in order to order to champion
Speaker 2: and establish its own smell, and there may be some
Speaker 2: level of territory marking when they lick or rub their
Speaker 2: faces against humans, certainly like the face rubbing, which can
Speaker 2: lead to licking or follow licking. You know, you never
Speaker 2: know how it's going to go. You know.
Speaker 3: I just had the thought that I wish I'd thought
Speaker 3: of this before we recorded, so I could look it up.
Speaker 3: But while I'm aware of lots of stories from legends
Speaker 3: where a dog licks a human's wounds, I can't think
Speaker 3: of anywhere a cat licks a human's wounds. Cat licks,
Speaker 3: or at least not in anonical literature that I know of, wound.
Speaker 2: Related Yeah, that's interesting. Well, maybe we'll come back to that.
Speaker 4: Yeah, all right.
Speaker 2: To close out this episode, I would like to talk
Speaker 2: a little bit about eye licking. In the last episode,
Speaker 2: we discussed the idea of eye licking as it fits
Speaker 2: into the magical and mythic concepts of the ancient Egyptians. Naturally,
Speaker 2: a lot of social grooming animals will lick each other
Speaker 2: in the face and in the eye. Come back to
Speaker 2: a couple of examples of that, but I wanted to
Speaker 2: touch on a couple of examples of animals that definitely
Speaker 2: lick their own eyeballs.
Speaker 3: Oh this is good.
Speaker 2: Yeah, And of course it's interesting to us humans because
Speaker 2: most humans cannot do this. To be sure, there are
Speaker 2: way most most My initial thought was, and I like
Speaker 2: my original original draft of the notes, as I was
Speaker 2: kind of putting my thoughts to, I was like, well,
Speaker 2: humans can't look their own eyes, so of course we
Speaker 2: find this interesting. But then I dared to look a
Speaker 2: little closer, and there are certain individuals who can, by
Speaker 2: some definitions, lick their own eyeball. WHOA like, it's going
Speaker 2: to come down to a few different measurements. So you know,
Speaker 2: facial spacing certainly, and you know there's a fair amount
Speaker 2: of variety there, but tongue size is the big one.
Speaker 2: I was looking around, and I believe the average human
Speaker 2: tongue link is between three and three point three inches.
Speaker 2: But you have certain individuals who have verified or unverified
Speaker 2: claims for almost four inch tongues. And then there are
Speaker 2: at least claims and I don't know, maybe not certified,
Speaker 2: but to my eye eyes convincing arguments for four inch tongues.
Speaker 2: One in particular I was looking at, again not verified
Speaker 2: by Guinness as far as I understand, but one Adrian
Speaker 2: Lewis of the United Dates. You can look her up
Speaker 2: because she was kind of like she appeared on various
Speaker 2: news programs and like did social media and YouTube videos.
Speaker 2: But she could stick out her tongue, which is allegedly
Speaker 2: four inches long, and then using her finger, guide the
Speaker 2: tongue up until it I think comes in contact with
Speaker 2: the eye, or perhaps could come in contact with the eye.
Speaker 3: I'm speechless, I like you assume, would have said no
Speaker 3: human can lick their own eye. This is if this
Speaker 3: is true, it's flabbergasting to me.
Speaker 2: Yeah, so it seems entirely possible that some humans can
Speaker 2: bring their tongue into contact with their eye, if not
Speaker 2: lick it in the same way that you know, an
Speaker 2: animal with a long tongue can't, like as well to
Speaker 2: get into in a bit like a giraffe and a
Speaker 2: a copy can do this like they can without a
Speaker 2: doubt lick their own tongue. Humans might have to have
Speaker 2: a little help, and therefore, you know, it's very hard
Speaker 2: to argue that there's any practical application for this.
Speaker 3: Yeah, not a doctor, but I would not recommend it
Speaker 3: for the same base reasons why there are downsides to
Speaker 3: licking your wounds. You know, you don't want to introduce bacteria.
Speaker 3: The mouth is a bacteria rich environment. You don't want
Speaker 3: to introduce microbes into a different place in the body
Speaker 3: when you don't have to.
Speaker 2: Yeah, yeah, So I'll come back to the mammal world
Speaker 2: real quickly because I have less to say about the
Speaker 2: mammal world, because the ocopy and the giraffe are great
Speaker 2: examples of related organisms. They both self groom via tongue licking,
Speaker 2: including licking of their own face, and they may lick
Speaker 2: their eyes in the process. They also lick each other
Speaker 2: during courtship. But the best example, the most exciting example
Speaker 2: of an animal licking its own eyes, you'll find this
Speaker 2: with geckos. Geckos or of course, reptiles of the suborder Gekkota,
Speaker 2: of which there are at least fifteen hundred known species.
Speaker 2: There are a lot of geckos out there. All geckos
Speaker 2: can and do lick their own eyeball, and the main
Speaker 2: reason for their doing so, again, it's not just to
Speaker 2: show off on social media. They do it to clean
Speaker 2: their eyes and remove debris from their eyes, such as
Speaker 2: little grains of sand, particles, and so forth. Some geckos, however,
Speaker 2: would seem to depend on this ability much more than others,
Speaker 2: as discussed by herpetologist Aaron M. Bauer in the book Geckos,
Speaker 2: The Animal Answered Guide. All geckos have eyelids, but if
Speaker 2: you read some descriptions of the scenario, will say, you know,
Speaker 2: a lot of geckos don't have islids. All geckos have eyelids,
Speaker 2: but only the thirty species of the u Blephylaridae geckos
Speaker 2: can move those eyelids. So it's one thing to have eyelids,
Speaker 2: but can you actually make them.
Speaker 4: Go up and down?
Speaker 2: Oh? Okay, interesting, So the Ublephalaridae geckos, they close their
Speaker 2: eyes and blink, much like we do. The gecko that
Speaker 2: my child has, a leopard gecko, is one of these geckos.
Speaker 2: So you know, this gecko can blink his little eyes.
Speaker 2: And I'm not sure that I've actually observed him licking
Speaker 2: his own eyes, but according to the literature, he can
Speaker 2: and does do so. I just I don't watch him
Speaker 2: all the time. I don't know what he's up to
Speaker 2: most of the day.
Speaker 3: Does the cat watch him?
Speaker 2: No, they don't interact. We don't want to encourage that anyway.
Speaker 2: They're in their own little worlds, you know. Though one's
Speaker 2: name is Waffles and the other's name is mochi, so
Speaker 2: they're kind they're kind of siblings in that regard. So anyway,
Speaker 2: we've discussed the blithelarid geckos. The non eu blifferid geckos
Speaker 2: cannot move their eyelids. They have a structure called a
Speaker 2: spectacle or brill that covers the eye and it protects
Speaker 2: it from abrasian and dryness. Bauer describes it as derived
Speaker 2: from a transparent lower eyelid that has become fused with
Speaker 2: the upper eyelid, so a trans and disc positioned directly
Speaker 2: over the eye, and it's it's very much you know,
Speaker 2: it's sometimes described as being like a scale. And indeed
Speaker 2: it is part of the gecko's skin. So when the
Speaker 2: gecko sheds its skin, which it will eventually eat. That's
Speaker 2: one of the magical things of having a pet gecko
Speaker 2: is when he goes into his hide to shed, he's
Speaker 2: going to clean all that up. He's not going to
Speaker 2: let any of that god of waste. But when he
Speaker 2: does shed, that eyelid is going to come off with it.
Speaker 2: I believe it becomes like you can tell, it becomes
Speaker 2: like kind of translucent, or you know, not translucent, becomes
Speaker 2: kind of like gray. Perhaps before it comes off Wow
Speaker 2: delicious now. Additionally, some of these geckos also have eyelid
Speaker 2: like structures called extra briller fringes that partially cover the
Speaker 2: upper portion of the eye and can be partially raised
Speaker 2: and lower, but they're not fold it's either way. The
Speaker 2: main function of self eyelid licking is to keep things
Speaker 2: clean and clear. However, they'll also just lick their eyes
Speaker 2: and faces to drink water droplets off their face. If
Speaker 2: they have water on there, why not, you know, free drink.
Speaker 2: They've also been observed licking their own face after eating
Speaker 2: or running, basically some sort of strenuous activity, but the
Speaker 2: reason for this isn't entirely understood. So in eating, of course,
Speaker 2: bear in mind we're talking about geckos. They are little predators.
Speaker 2: They are eating live prey, so that there's an endurance
Speaker 2: aspect to that as well. Elsewhere in the book, Bauer
Speaker 2: notes that geckos often lick one another during courtship, and
Speaker 2: this is likely both tactile and chemical communication, with molecules
Speaker 2: on the tongue transferred to their vomeroonasal organ to then
Speaker 2: crunch the data about potential mates.
Speaker 3: Oh coming back to like the like the snakes. Yeah, yeah,
Speaker 3: the Jacobson's organ.
Speaker 4: Yeah.
Speaker 2: So if you have a gecko out there, you know,
Speaker 2: to watch them a little extra in the next couple
Speaker 2: of days. See, first of all, recall what sort of
Speaker 2: gecko you have, and see what sort of eye licking
Speaker 2: us up to. And if you can lick your own eyeball,
Speaker 2: don't do it. For starters. I encountered similar things looking
Speaker 2: into this, the idea of humans locking eyeballs, because for
Speaker 2: a subset of the human population, there is a certain
Speaker 2: eroticism to the licking of another human beings eye balls. Yeah,
Speaker 2: but you know, I mean, there's there's room for everything.
Speaker 2: I'm not going to shame anybody, but.
Speaker 3: This is judging. I'm just surprised.
Speaker 2: But this is not recommended by health experts. It's it
Speaker 2: kind of comes back to the dog looking a wound scenario.
Speaker 2: It's like, yeah, we have better ways to attend to
Speaker 2: the cleanliness of our eyes. So no need to have
Speaker 2: your eyes licked by even you know, even a trusted lover.
Speaker 2: But if you were a get go, I mean, go
Speaker 2: at it.
Speaker 3: It's your way of life.
Speaker 2: All right. We're going to go and close the book there,
Speaker 2: but we will be back so tune in for more
Speaker 2: episodes in the future. Just to remind it of the
Speaker 2: Stuff to Blow Your Mind is primary science and culture
Speaker 2: podcasts with core episodes and Tuesdays and Thursdays. On Wednesdays
Speaker 2: we do a short form episode, and on Fridays we
Speaker 2: set aside most serious concerns to just talk about a
Speaker 2: weird film on Weird House Cinema.
Speaker 3: Huge thanks as always to our excellent audio producer JJ Posway.
Speaker 3: If you would like to get in touch with us
Speaker 3: with feedback on this episode or any other, to suggest
Speaker 3: a topic for the future, or just to say hello,
Speaker 3: you can email us at contact at stuff to Blow
Speaker 3: your Mind dot com.
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